A shot-putter exerts an unbalanced force of 140 N on a shot giving it an
acceleration of 19 m/s2. What is the mass of the shot?

7.37 kg

Explanation:

By Newtons Second Law of Unbalanced Forces

Force = Mass × Acceleration

140N = Mass × 19m/s^2

Mass = 140N / 19m/s^2

= 7.37 kg

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.